Former D.C. mayoral candidate Sulaimon Brown, who said he was paid by Mayor Vincent Gray’s campaign to undermine then-incumbent Mayor Adrian Fenty, called on Gray to resign after one of the mayor’s campaign staffers pleaded guilty to providing funds to Brown, destroying evidence and obstructing the investigation into the case and another was accused of lying to FBI agents during the investigation.

“I was not looking for vindication for truth need not be vindicated,” Brown said in a statement to The Washington Post. “I was seeking justice.”

He also said, “Mayor Gray should resign immediately if not sooner for his violation of not only me, but the public trust of The District of Columbia residents.”

The Post reported Brown’s allegations last year that he was paid to stay in the 2010 Democratic primary campaign to attack Fenty. The story triggered a federal investigation into the allegations.

Gray has denied knowing about the payments, but on May 22, Thomas W. Gore, assistant treasurer of Gray’s 2010 mayoral campaign, pleaded guilty to a felony count of obstruction of justice for shredding a spiral notebook that prosecutors have said contained a record of the payments. He also pleaded guilty to three misdemeanor counts of making a contribution in someone else’s name.

The campaign took another hit on May 23 when charges were filed against Howard Brooks, 64, a consultant who worked on the Gray campaign’s treasury and financial teams. Brooks was accused of lying to FBI agents when he denied giving cash or money orders to a minor mayoral candidate in the 2010 campaign. In fact, prosecutors have alleged, he gave Brown, hundreds of dollars to help Brown, a marginal candidate, stay in the race to continue assailing Fenty.

Federal authorities also are investigating prominent D.C. contractor Jeffrey Thompson, his ties to Gray and his administration and D.C. Council members. In March, Thompson’s home and offices were raided by federal agents and several council members have been served federal grand jury subpoenas, seeking details about their contacts with Thompson.